18x2 -13x +2 = 0
ax2 bx c = 0
a = 18
b = -13
c = 2
Δ = b2-4ac
Δ = -13² - (4 * 18 * 2)
Δ = 169 - (4*36)
Δ = 169 - (144)
Δ = 25 Δ > 0
18x2-13x+2=0
x = -b ∓ √Δ 2a
x' = 13 - √25 2*18 = 13 - 5.0 36 = 8.0 36 = 0.222222222222
x" = 13 + √25 2*18 = 13 + 5.0 36 = 18.0 36 = 0.5
x' = 72.0
x" = 162.0
S = {x ∈ R / x' = 72.0, x" = 162.0 }